This application claims the priority of German application 198 39 527.2, filed Aug. 29, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a locking device for a steering column for a motor vehicle. The steering column is arranged such that it can be adjusted with respect to the motor-vehicle body and has a locking device for releasably securing the steering column to the motor-vehicle body, which device comprises a first locking element on the steering column and a second locking element on the body, the two elements being able to be adjusted in relation to the other in a release position, which allows the steering column to be adjusted, and in a locking position, which secures the steering column. The invention also relates to methods for making and using the above-mentioned locking device.
Patent document EP 0 440 403 B1 discloses a steering column for a motor vehicle, which is secured releasably to the motor-vehicle body via an adjustable locking device. The locking device comprises a mounting which is secured on the body and has a tooth arrangement and a locking element which can be moved in the mounting and has a corresponding tooth arrangement. The moveable locking element is connected to the steering column via at least two connecting elements. Parts of it are of resilient design such that it can be brought, via a lever, into engagement with the tooth arrangement on the mounting secured on the body and can automatically lift itself off the tooth arrangement. The locking device therefore permits the steering column to be adjusted, in particular transversely to the axial direction of the steering column, in a stepped manner corresponding to the tooth width of the toothing. The number of possible latching positions of the locking device is determined by the number of engagement possibilities of the toothing.
The object of the invention is to provide a steering column of the type mentioned at the beginning which can be adjusted in an infinitely variable manner with respect to the motor-vehicle body, and whose locking device is of particularly simple design.
This object is achieved in that at least one of the locking elements is designed as an elastically ductile deformation element which can be deformed in the locking position by means of the other locking element with resultant force or form locking of the steering column to the vehicle body. The elastic deformability of at least one locking element makes it possible for a reversible contact to take place between said locking element, which is designed as the deformation element, and the further locking element or the steering column or motor-vehicle body. The homogeneous ductile behavior of the deformation element means that the steering column is able to be secured with respect to the motor-vehicle body in an infinitely variable manner.
In a refinement of the invention, the first locking element is designed as the deformation element and is connected fixedly to the steering column. The second locking element is preferably of rigid design such that it engages positively and frictionally on the first locking element, as the latter is being deformed, and in this case fixes the first locking element, including the steering column, on the body.
In a further refinement of the invention, in the direction of the steering-column axis, the deformation element is of a length which at least approximately corresponds to the adjustment travel of the steering column in the axial direction. The steering column can thereby be arranged such that it can be adjusted relative to the second locking element on the body, the locking element on the body engaging on a different point on the deformation element when the steering column is in a different relative position.
In a further refinement of the invention, the deformation element is designed as a hollow profile, in particular consisting of a highly elastic rubber material. By this means, particularly reliable, flexible ductile behavior of the deformation element is ensured.
In a further refinement of the invention, the second locking element is secured in a pivotable manner to the motor-vehicle body. As a result, the second locking element can be adjusted in a simple manner by being pivoted against the first locking is element.
In a further refinement of the invention, the second locking element has a lug which presses it into the first locking element. In this case, the first locking element is preferably designed as the highly elastic deformation element and the second locking element as a dimensionally stable cam.
In a further refinement of the invention, the second locking element is assigned at least one stop which is secured on the body and against which the second locking element abuts in its locking position. Since the positive engagement of the second locking element in-the first locking element, which is designed as the deformation element, does not suffice on its own to unambiguously and mutually secure the elements, a further stop which is secured on the body constitutes an additional means of fixing for the locking device. Particularly when a second locking element is secured in a pivotable manner to the motor-vehicle body, the stop which is secured on the body serves to limit the pivoting movement, with the result that the second locking element is retained in its locking position.
In a further refinement of the invention, the second locking element can be adjusted with respect to the motor-vehicle body, in the direction of the adjustment travel of the steering column, and can be secured separately. This enables the second locking element to track an adjustment of the steering column, so that it can in each case be positioned opposite the first locking element.
According to a second aspect, the invention provides a method for making a locking device for releasably securing an adjustable steering column to a motor-vehicle body. This method comprises providing two locking elements: a first locking element designed as an elastically ductile deformation element and a second locking element with means for deforming the deformation element into a locking position. One of the two locking elements is attached to the steering column and the other locking element is attached to the motor-vehicle body.
Another aspect of the invention provides a method for releasably securing an adjustable steering column to a motor-vehicle body. This method comprises attaching a locking element to the steering column and attaching another locking element to the motor-vehicle body. One of the two locking elements is designed as an elastically ductile deformation element that can be deformed in the locking position by means of the other locking element with resultant force and/or form locking of the steering column to the motor-vehicle body.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.